Could vitamin C during pregnancy play a role in how babies respond to stress and frustration? A new study suggests it might, although the findings raise as many questions as they answer.
Researchers at Oregon Health & Science University followed 302 pregnant women and found that those who consumed more vitamin C through supplements tended to have babies who showed less fussiness, sadness and distress at 6 months old. The findings, published in Developmental Psychology, suggest a possible connection between prenatal nutrition and early emotional development, but they don't prove that vitamin C supplements were responsible.
The researchers were particularly interested in how nutrition might affect babies whose mothers experienced stress, anxiety or depression during pregnancy. Previous studies have found that higher levels of prenatal stress are associated with differences in infant temperament, including a greater tendency toward fussiness and frustration.
Vitamin C was a natural candidate to investigate. The nutrient helps protect cells from damage, supports iron absorption and plays an important role in fetal development. During pregnancy, babies depend on their mothers to supply the vitamin C they need.
To explore the relationship, researchers assessed women's stress, anxiety and depression levels late in pregnancy. They also examined what participants ate and which supplements they took, including prenatal vitamins.
When the babies were approximately 6 months old, caregivers answered questions about their behavior, including how often they became frustrated, cried or showed signs of distress.
The researchers found something unexpected: Higher vitamin C intake from supplements was associated with less negative emotional behavior in infants, but vitamin C from food did not show the same connection.
That doesn't mean supplements are better than fruits and vegetables. Researchers couldn't determine why the difference appeared, and women who regularly take supplements may have other health habits that influence their children's development.
The study also found that women experiencing greater stress, anxiety and depression during pregnancy tended to consume less supplemental vitamin C. Their babies, in turn, were more likely to show higher levels of fussiness and distress.
"The most encouraging takeaway here is that nutrition is relatively modifiable, especially when people have adequate resources and support," said senior author Elinor Sullivan, Ph.D., a professor of psychiatry and behavioral neuroscience at OHSU.
But there are important reasons to be cautious about the findings.
The study was observational, meaning researchers tracked participants' existing habits rather than assigning them to take vitamin C supplements. That makes it impossible to know whether vitamin C itself influenced infant behavior or whether other factors played a role.
Researchers also relied on caregivers' descriptions of their babies' behavior. They didn't directly measure brain development or determine whether the children would experience mental health problems later in life. And while fussiness and frustration can be associated with later emotional difficulties in some children, they're also normal parts of infancy.
For pregnant women, the research doesn't change existing nutrition recommendations. Vitamin C is essential during pregnancy, and adults ages 19 and older need approximately 85 milligrams daily. Citrus fruits, strawberries, bell peppers and broccoli are good sources, and many prenatal vitamins also contain vitamin C.
The findings don't establish that taking extra vitamin C improves a baby's temperament. Pregnant women should discuss supplements with their health care provider rather than increasing their intake based on this study.
Researchers hope to follow the children as they grow to learn whether the early differences in temperament persist. Additional studies will also be needed to determine whether vitamin C supplements themselves can make a meaningful difference in children's emotional development.
The research received funding from the National Institutes of Health, including the National Institute of Mental Health and the National Center for Advancing Translational Sciences.